FOOLED BY NUMBERS : How Simple NUMBERS Can Lead You Astray

 

Let’s start with a classic river problem. The average depth of the river is 5 feet, and your height is 6 feet. Would you cross the river by walking?

A person with a good understanding of averages would likely not choose to cross the river. Here’s why: When we say the average depth of the river is 5 feet, it means that at some points, the depth may be only 1 foot, at other points, it may be 2 feet, and in some areas, it could be as deep as 15 feet. Now, imagine stepping into a spot where the river’s depth is 15 feet. This is the danger of relying only on averages.

This analogy applies to investment data as well. When returns are presented as averages, it’s crucial to rethink the information.

For example, consider this: The average return of the Nifty 50 is 12% over 10 years. On the surface, this looks like a reliable and stable investment strategy: invest in the Nifty 50 and expect a 12% return per year. But this average hides a lot of crucial information about the volatility and risk involved.

Let’s break it down: In year one, there might be a 10% gain, in year two, a 15% gain, but in year three, there might be a 20% loss, followed by a 5% gain, and so on. The misleading simplicity of averages is that it only tells you the end result, ignoring the journey—the dramatic ups and downs, the pain of market crashes, and the timing of when you invest. This is why, when evaluating investments, it’s important to check rolling returns to get a clearer picture of how an investment performs over time.

If getting fooled by averages is one problem, then getting fooled by percentages is another. We often assume that a percentage increase is the same as a percentage decrease, but we ignore the base reference. 

For example: if you buy a stock for ₹100, and it goes up by 10%, the new price is ₹110. But if it then drops by 10%, it doesn't go back to ₹100—it goes to ₹99. This happens because the percentage change is always based on the current value.

Here’s another example:

A 10% return for 10 years doesn’t mean you simply multiply the initial amount by 10%. It’s 10% compounded per year. A 10% return compounded annually for 10 years leads to a substantial gain—you end up with 259% growth over 10 years, not just 100%.

Another key takeaway is that when evaluating long-term investments, looking at the absolute return percentage can be misleading. Instead, we should focus on the Compounded Annual Growth Rate (CAGR), adjusted for inflation and taxes, to get a true understanding of how your investment is growing in real terms.

conclusion : It is rational to rely on numbers, but the context in which you view them plays a critical role. For instance:

• Averages tell you the overall trend but ignore the volatility and timing risks.
• Percentages are useful but need to be understood in relation to the base value and compounded over time.
• Real returns adjusted for inflation and taxes reflect your actual purchasing power and are key to understanding the true growth of your investment.

Therefore, the next time you assess an investment, take a step back to understand the context behind the numbers. Look beyond the surface and consider how compounding, volatility, inflation, and taxes shape the true outcome of your investments. Only by doing this will you have a clear and accurate picture of what your money is really doing for you in the long run.